counter for books
「冊」 has another reading with different meanings.
imperial edict to confer nobility titles (in ancient China)
本を三冊買って家に帰った。
I bought three books and went home.
雑誌が本棚に五冊並んでいる。
Five magazines are lined up on the bookshelf.
一冊読み終えて満足しました。
I finished reading one book and was satisfied.